Pressure-relief means



July 31, 1928.

\ M. J. GOLDBERG PRESSURE RELIEF MEANS Filed April 1, 1927 Patented July 31, 192 8.

UNITED STATES PATENT OFFICE.

MORRIS J. GOLDBERG, OF BELOIT, WISCONSIN, ASSIGNOR TO FAIRBANKS, MORSE & CO.,

- OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

' PRESSURE-RELIEF MEANS.

Application filed April 1,

This invention relates to improvements in pressure relief means, and more particularly to an improved device for unloading, or re lieving compression in, the working cylinder of an engine or an air compressor.

An object of this invention is to provide 7 an improved, more simple means for manually or automatically retaining a cylinder valve in open position. I a

A further object is the provision of a device for the above purpose, which need comprise only a single element, for effectively and selectively rendering a valve operative or inoperative.

A further object is an improved compression relief means applicable to any usual type of internal. combustion engine or air compressor and adapted particularly to serve as an unloading means for an air compressor and for use with an automatic pressure-regulated unloader.

Further objects and advantages 'of this invention will appear from' the following detailed description.

My improvement consists in the novel construction, arrangement and combination of parts as hereinafter fully, clearly and concisely described, definitely pointed'out in my claims and illustrated by the accompanying drawings in which:

Fig. 1 is a sectional elevation of the head and a portion of the working cylinder of an air compressor to which an approve form of my device is applied;

Fig. 2 is an enlarged elevation of an improved form of my unloading shaft, adapted for an air compressor having a pair of suction valves, and showing diagrammatically the position of the shaft relative to the valve stems.

The structure of the unloading shaft and related parts, their relative disposition with respect to the cylinder, the means for mounting the unloading device, may be varied in form without departure from the spirit of my invention as hereinafter described and claimed, the showing of this description and the drawings being merely an illustration of one embodiment of my invention in compliance with the statutory requirements relating to application for a patent.

Referring by numerals to the drawings, a working piston of preferred form is indicated at 5, and contained within cylinder T Walls 6. The head portion of the cylinder 1927. Serial No. 180,292.

' take valve 8 and a discharge valve 9. The

intake valve is yieldingly retained in its closed position by a spring 10. The valve 8 is provided in the usual manner with a seat 11 and a stem 12. In the construction shown, an air intake passage is indicated as 13.

Preferably located at about a right angle to the aXis of the valve stem 12 is an unloading shaft 14. The shaft 14 may have any desired position in a plane which is preferably at substantially a right angle to the line of movement of the intake valve. As a housing member, and as a means for positioning the bearings for shaft 14,'I prefer to provide a cover 15. The cover 15 may serve as well to protect the shaft and related parts from dust and foreign substances and may serve to confine a lubricant about the shaft. The shaft 14 may be journaled in bearings which are formed integrally with the head 7, or carried thereby, or, if preferred, a hearing such as indicated diagrammatically at 19 may be cast integrally with the cover 15. The unloading shaft proper comprises a shaft having a plurality of portions of reduced diameter. In the example shown these portions of smaller diameter are shown at 16 and are spaced on the shaft a distance corresponding to the distance between centers of adjacent intake valve stems. The

d unloader shaft illustrated is'designed for a compressor having dual intake valves, hence the provision of two of the portions of reduced diameter 16. Adjacent the portions 16 of the shaft are other portions of the normal diameter of the shaft designated as 17. At one or both ends or upon any exposed portion of the shaft is preferably located an operating means of suitable form, such as the knob or handle 18. Shaft bearings of conventional form are indicated diagrammatically at 19 in Fig. 2. As a means for retaining the unloader shaft 14 in either its operative or inoperative position, the eXecutional-example shows a spring pressed retaining plunger 20. The plunger 20 operates in retaining grooves 21, in shaft 14, and is yieldingly forced into the grooves by a spring 22 resident in a socket 23 for the plunger and spring. In lieu of the spring pressed plunger 20, I may use any other suitable means for positioning the shaft 14.

I have illustrated the shaft 14 as having a iii) diameter substantially equal to the enlarged portions 17 thereof. Obviously, a shaft may be used which has an initial diameter such as shown by the reduced portions 16. In this case the enlarged portions 17 may be provided by suitably formed collars or by protuberances upon the shaft itself. The form illustrated has the advantage of being easily and cheaply manufactured, the shaft being turned down from the usual diameter shown at 17, to form the portions 16 of reduced diameter, .and the retaining grooves 21.

The operation of my device will be at once apparent from the above detailed description of parts. unloading device of this sort is especially suitable for a 'posi. tively driven air compressor in installations in which it is impractical to provide a means for disconnecting the compressor from the pri ne mover. Such an installation is often used for pumping air intothe air-start re-. ceivers of oil engines for marine use. A relief means such as herein shown is provided in order that the compressor may cease delivery when the receiver is pumped up to normal capacity. Such relief is accom-' plished by'holding the intake valve 8 from its seat. When the compressor is operating, the upper end of the valve stem 12 is oper ating in 1a relieved portion 16 of the unloading shaft. The suctionvalve is thus permitted to open and close normally. The movement of shaft 14 along its axis causes one of .the portions of larger diameter 17,

to contact with the end of Valve stem 12, thus holding the valve off its seat.

It will be seen that the arrangement described provides a simple and sturdy unloading device wh'ich may be used in any situation in which it is desired to hold a valve away from its seat for any purpose whatsoever. The same arrangement may be used for relieving compression inthe working cylinder in an internal combustion engine for starting, timing, or other purposes.

It will be seen that this devicecan be manufactured at a very low cost by turning down in a suitable manner, an ordinary steel shaft. Due to the position of the shaft with respect to the working cylinder, it is easily accessible and may be removed or installed:

be moved transversely to the path of travel 7 of said valve; a portion of the valve nor? mally operating adjacent one of the reduced portionsof' theshaft, and a shaft positioning means adapted to coact with other of said reduced portions toposition the shaft definite y in ach f ev l p sitions- 2. In an unloading device for an air com-. pressor havinga cylinder and ,a valve in the cylinder, a shaft having a pluralityof pore tions of reduced diameter and arranged to be moved transversely to the path of'trjavel ofsaid valve 5 a portion of the valve normally operating adjacent one of the reduced portions of the shaft, means for moving the shaft axially in either direction, whereby the valve is held open adjacent a ortion of the shaft of normal diameter, anc a shaft positioning means adapted to coact with other of said reduced'portions to position the shaft definitely 'in each of a plurality of positions.v

3. In an unloading device for an air compressor having a cylinder and a valve in the cylinder, a control shaft having a plurality of portions of reduced diameter and arranged to be moved transversely to the path of travel of said valve 5 a portion of the valve normally operating adjacent one of the reduced portions otthe shaft, and a shaft positioning means comprising a springeo pressed plunger" disposed transversely to the. shaft and adapted to coact with other of said reduced portions to position the shaft definitely in each of a plurality ofpositions;

MORRIS GQLDBJERG. 

